644554360261344 has 192 divisors, whose sum is σ = 1862838979900416. Its totient is φ = 193899765295104.

The previous prime is 644554360261333. The next prime is 644554360261367. The reversal of 644554360261344 is 443162063455446.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 49745374 + ... + 61349090.

It is an arithmetic number, because the mean of its divisors is an integer number (9702286353648).

Almost surely, 2^{644554360261344} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644554360261344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (931419489950208).

644554360261344 is an abundant number, since it is smaller than the sum of its proper divisors (1218284619639072).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644554360261344 is a wasteful number, since it uses less digits than its factorization.

644554360261344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11604737 (or 11604729 counting only the distinct ones).

The product of its (nonzero) digits is 99532800, while the sum is 57.

The spelling of 644554360261344 in words is "six hundred forty-four trillion, five hundred fifty-four billion, three hundred sixty million, two hundred sixty-one thousand, three hundred forty-four".